1. Field of the Invention
The present invention relates to an image pickup apparatus, an image pickup system, and a driving method of an image pickup apparatus.
2. Description of the Related Art
As an image pickup apparatus used for an electronic video camera and an electronic still camera, an image pickup apparatus called an X-Y addressing-type sensor is known. In the X-Y addressing-type sensor, a signal can be obtained from a pixel at a specific position by specifying an address. By this feature, in the X-Y addressing-type sensor, it is possible to realize an all-pixel read mode in which signals are obtained from all the pixels, a thinning-out read mode in which a part of rows or columns are skipped and signals are obtained from the other pixels, and the like.
Japanese Patent Laid-Open No. 2000-350103 describes that in a thinning-out read mode, pixels in a row from which signals are not read, in other words, pixels in a skipped row are fixed to a reset state at all times.
Japanese Patent Laid-Open No. 2008-288903 describes that a first storage means for storing an address of a row in which a shutter scan is performed and a second storage means for storing an address of a row in which a read scan is performed are provided in order to perform a complex shutter operation in a thinning-out read mode. Also a pixel sharing technique is described in which a floating diffusion portion, which temporarily holds a charge accumulated in each pixel, is shared by a plurality of pixels, and further, a circuit for selecting a pixel at that time is described.
In Japanese Patent Laid-Open No. 2000-350103, a row to be thinned out is fixed. Hence, it is difficult to freely change the row to be thinned out.
According to the technique of Japanese Patent Laid-Open No. 2008-288903, a row to be thinned out can be freely set because a decoder is used. However, Japanese Patent Laid-Open No. 2008-288903 only has the first storage means for storing an address of a row in which the shutter scan is performed and the second storage means for storing an address of a row in which the read scan is performed, so that the row to be thinned out cannot be always held in a reset state.